transponder on c mode when on taxiway KLAX?

[wingtip777]

HELLO, ALL.
jeppesen says we should turn on transponder on c mode in KLAX when on taxiway. does that mean we should turn the transponder switch to "TA ONLY "OR "TR\RA" position in KLAX for Boeings? nomally we turn the transponder on XPOND position during taxi.
when KLAX ATC say"CHECK YOUR TRANSPONDER ON", at that time it was on XPONDER position. does that mean"turn on your transponder"or "turn off your transponder"?
thanks to any reply!

[Ndicho Moja]

If you are operating S Mode transponders selecting ATC from STBY to AUTO will allow ground control to interrogate/monitor your aircraft while taxiing without transmitting altitude data.

[westhawk]

FAA standard procedure for ASDE-X equipped airports is to select XPDR or ON as appropriate. Of course, company manuals should specify transponder operating procedures for each airplane type. Apparently, FAA inspectors conducting enroute inspections have noted inconsistencies between certain operators according to this recent issued InFO. (http://www.faa.gov/other_visit/aviation_industry/airline_operators/airline_safety/info/all_infos/media/2011/InFO11012.pdf)

[wingtip777]

Ndicho Moja、westhawk
thanks!
our transponder is s mode, the switch was on XPDR(we don't have AUTO positon) as usually. but ATC said to us:"CHECK YOUR TRANSPONDER ON" , that confused me, wondering if there is any spesial procedure for KLAX. according to the info, XPDR should be the correct position to switch on KLAX TAXIWAY.

[westhawk]

XPDR should be the correct position to switch on KLAX TAXIWAY.

Agreed. Maybe they were having trouble with their ASDE-X equipment that day. I've also heard of some airplanes having a transponder ground inhibit tied to the air/ground sensing,(Squat sw or WOW) but that should have been addressed years ago with the introduction of ASDE-X.